United States diplomat in China has brain injury after hearing 'abnormal' sounds

The U.S. Embassy in China issued a health alert Wednesday to all government workers after an employee showed signs of a brain injury after hearing "abnormal" sounds and feeling unusual physical pressure.

A United States Government employee in southern China has reported suffering from "abnormal" sounds and pressure leading to a mild brain injury, the U.S. embassy said - recalling similar experiences among American diplomats in Cuba.

Wednesday's alert said the US government does not know the cause of the reported symptoms and has not received similar reports in other parts of China, but that it is taking the report seriously.

United States diplomatic officials said they could not link the case to health issues suffered by USA government staff in Cuba dating back to late 2016. "Instead, move to a location where the sounds are not present", it says, urging people with medical problems to consult a doctor. At least two Canadians were also affected.

For most, the symptoms occurred around May 2017.

Though the State Department has not linked this case to any other incident, news of unusual symptoms hitting US government employees overseas will no doubt draw comparison to a rash of incidents with USA and Canadian diplomats working in Cuba. The worker was sent back to the United States for medical evaluation.

The State Department was taking the incident very seriously and working to determine the cause and impact, the embassy said.

CNN has reached out to China's Ministry of Foreign Affairs but has not yet received a response on this matter.

The embassy spokesperson told CBS News that the Chinese government had "assured us they are also investigating and taking appropriate measures".

Officials initially suspected the Americans had been targeted by an acoustic weapon, but media reports have suggested that the Federal Bureau of Investigation has been unable to verify any evidence to support that theory. Media reports have suggested that the Federal Bureau of Investigation has not been able to verify any evidence to support the sonic weapon theory.

The US previously said its diplomats in Cuba had suffered similar symptoms after suspected sonic attacks. State Department said in its health advisory posted online Wednesday.

Canada announced last month that it was bringing home the families of its diplomats in Cuba after a year-long investigation into the illness failed to reveal a cause.